Sound reproducer



July 7, 1936. p -L JENSEN 2,046,515

SOUND REPRODUCER Original Filled June 27, 1930 2 Sheets-Sheet l P. .JENSEN 2,046,515

SOUND REPRODUCER July 7, 1936.

original Filed June' 27, 1930 2 sheets-sheet 2 auf Patented July 7, 1936 PATENT OFFICE SOUND REPRODUCER Peter L. Jensen, La Grange, Ill., assignor to Jensen Radio1 Manufacturing Company, Chicago, `Ill., a corporation of Nevada Original application June 27,",1930, Serial No. 464,275, now Patent No. 1,941,476, January 2, 1934. Divided and thisV application June 17,

1931, Serial No. 544,987

1 Claim.

My invention relates to sound 'reproducera particularly of the electro-dynamic or moving coil type, in which the coil is disposed so as to be freely movable in an annular field between the inner and outer pole pieces.y Y The. present application is a division of my copending application Serial No. 464,275, led June 27, 1930, and relates to improved means for concentrically disposing the pole pieces with respect 1 0 to each other. f V

The invention is illustrated in the accompanying drawings, in which: Figure 1 is a fragmentary section taken longitudinally along the axis of adevice embodying the invention;

Figure's2 and 3 are more or less diagrammatic sectional views partially in elevation, and showing the steps'of forming the positioning means on the case and end plate parts, respectively;

Figure 4 is a more or less diagrammatic view i' similar to Figure 2, showing an alternative manner' of forming the positioning vmeans on the case part; l Figure 5'is afmore or less diagrammatic view similar'to FigureS, showing an alternative man- .ner of forming the positioning means on the end Aplate part; p Y

5 Figure 6v is an end View on a reduced scale of theA device shown in Figure 1; Y 30 Figure 7 isa longitudinal axial section through the case and end plate parts, showing a modied form' of *positioningV means on the parts; and `Figure`s 8 Aand -9 are more or less diagrammatic -viewsshowin'gthe steps of forming the positiont ing means shown in Figure 7.

` Referring to the drawings, the device shown in Figure 1 comprises a case 5, inner pole piece or core 6, and an end plate'.1 Aconstituting the circumferential outer pole piece. A frameV 8 has a radial-,portion Ssecured to Ythe plate 1 by rivets I8, and'froml the radial por- Ation 9 the frame 8 extends generally conically 4 and is Vof `open Work formation at II. For increasing the magnetic area or depth in the outer pole piece 1 a supplemental outer pole piece ring I2 is secured to the pole piece 1 bythe rivets I0, the radial portion .9 of the frame 8 being oiset at 50 I3 to accommodate it to the interposed ring I2. The generally conical diaphragm I4 is yieldingly attached around its outer periphery at I5 to the Vframe 8, and its inner truncated end is rigidly secured at I 6 to an' insulating coil carry- 55 ing sleeve I1. The ymovable coil I8 is wound upon and preferably rmly cemented to the outer surface'of the sleeve I1.

The inner pole or core piece 6 is riveted or rigidly secured at I9 to the end 20 of the case' 5, which end 2D may be provided With a ring piece 5 2I for increasing the magnetic area. A magnetizing coil 22 may be placed around the core 6, beinginsulated therefrom by an annular layer of insulation 23.

The-pole piece 1, I2 is provided with a circular 10 opening 24 through which the adjacent end of the core 6 extends in the assembled relation of the'parts, the diameter ofthe opening 24 being sufficiently great to admit the coil I8 and sleeve I1 which surround the core 8 and which are 15 freely movable4 in the annular eld between the inner and outer pole pieces. Insulating rings 25 and 2G are disposed at the opposite ends of the "coil 22, a brass spacing ring 21 offset marginally `at 28 being loosely interposed between the ring 20 25 and the pole piece 1. The inner truncated end I6 of the diaphragm `I4 is'anchored for free movement with the coil 22'b`y non-radial spring arms 39 secured at their outer ends'to lugs 3| struck up from the frame 3, 25 and at their inner ends to a ring element 32 surrounding the sleeve I1, and between which and VYthe sleeve I1 the adjacent end of the diaphragm I4 may be secured. Y Y Y The case 5 is flanged radially at 35 and may be 30 secured to the pole piece I and frame 8 by screws 36 passing loosely through registering openings 31 and having threaded engagement in nuts 38.

Now, in order to dispose pole pieces 6 and 1 concentrically with respect to each other, I pro- 35 vide the flange 35 of one pole piece part, namely, the casing 5 Withpositioning means 4l) and the other pole piece part, namely, the pole piece 1 itself is provided with positioning means 4I which engage with the positioning means 40 and dis- 40 pose the pole pieces 6 and 1 concentrically, -thereby forming a uniform annular space between the inner and outer pole pieces and assuring a uniformity of the eld by the simple expedient `of assembling the parts.

In the embodiment of Figures 1, 2 and 3 the m positioning'means 40 is in the form of a plurality of dowel sockets or openings preferably equidistant apart circumierentially around the ange 35, the positioning means 4I comprising cooperating and similarly positioned dowel pins on the polev piece 1. The dowel pin's 4I are shown as being pressed or extruded out of the metal of the pole piece 1, but separate pins may be at- 5.5

Yferal Ypositioning sockets. vthe means for forming the cooperating rposi- ,pole piece 1.

The forming elements, therefore, may be in the D form of drills 45, one being shown for each* socket or opening 40, and these drills arecarried by a carriage 46 having movement toward and from the case supportlll. Thel forming elements are spaced according to the desired spacing and arrangement of positioning means 40. A centering element 48 also carried by the carriage 46 has a socket 49, the axis of which is equ'idis-l tant from the axes of the drills or socketY forming elements 45. The internal diameter of the socket 49 is equal to the external diameter of the pole piece 6, and the lower end of the socket 49 flares outwardly and projects below or beyond theends of the forming elements 45 suiciently to take overthepole Vor core piece 6 and center the same Withrespect to the socket forming elements 45 ahead of the operation of these .elements 45 upon theflange 35. A ring 50 on the support positionsy the case 5 for centering cooperation of the centering element 48 with the core 6.

With the case 5 centered by means of the core 6 with respect to the elements 45 for-forming the Vpositioning means 46, this means 46 is formed -by the elements 45 upon continued movementof the'carrier 46 toward the support 41. Upon `forming the positioning means the forming elements may be Withdrawn and the next case arranged 'in placeand similarly operated upon.

While Iv have shown and described the forming means'45 as a plurality of elements, itis to be "understood that one element might be employed andthe carriage arranged to be turned to bring it into position for successively forming the sev- |Ihis also applies to tioning means 4l on the outer pole piece 1,.

In Figure 3 is shown the step of forming the Vpositioning -dowels 4l on the pole piece 1, these -doWels 4I being shown as pressed or extruded vfrom the metal of the pole piece 1, but may be in the form of separate pins appliedaccording to this invention to form the doWell means; In the `embodiment shown the forming means comprises a die-like block 52 recessed at 53 to receive the pole piece 1- and provided With'an axial opening 54 rto admit fthe centering element 55-of the plunger V56 Which is movable toward and from vthe block 52 and has extrusion elements 51 forv `cooperating with extrusion recesses 58 in the vblock 52 so that upon-movement of the plunger V tovvard the block 52 these elements will by their. engagement With the polepiece 1 and by their cooperation with the-recesses 58 extrude thevfdowel pin means 4l fromfthe metal of the @The axes of the extrusion elements .51 are equidistant from the axis of the centeringele- `ment ,55, and the external diameter of the cen- ,tering ele-ment 55 is equal' to theinternal diameter of the opening 24 in the pole piece 1, and its lower end is tapered at 68 and projects below the Yelements 51 suiciently to enter the openingk 24 andlcenter the pole piece 1 withV respect to the Yelements 51`ahead of the operation of these ele*- Yments uponY the piece 1. Clearance is shown in the' block 52 around the piece A1 to permit this centeringg'and a slight clearance isshoWn bepiece 6 is associated with the support 41instead .secured together Vbefore the formation of the podowel pin element 4l into the dowel socket 40 will, accurately dispose the pole pieces in concen- Y tric relation Without adjustment and by the simple expedient of assembling the parts. Y

In Figure 4 the means 49 for centering the forming elements 45 by means of the inner pole `15 of-With the carriage 46', asin Figure 2, it being understood that the elements 45 are centered jequidistantly from the axis of themember 49.

In Figure 5k the centering element 55 for centeringA ther forming elements 51` by meansl of 20 the pole piece-opening 24"is associated With the Y block52''inste`ead` of With the plunger56'" as in Figure 3, it being understood that'the elements 51 are centered equidistantly from the axis of the member 55. y In the embodiment illustrated in Figure? the positioning means on the case 5a Vcomprises thev radial flange 65, the periphery of Which is vturned down about the inner pole piece 6a carried by the case 5a as a center, and the cooperating position- 30l ing means on the'pole piece 1a is formed by turning the marginal edge ofthe pole piece 1a over marginally at 66 to embrace the periphery of the ilange to th'erebydispose the pole pieces of these partsy concentrically with respect Vto each 35 other.

In Figure 8 the case'5a; is shown more or less diagrammatically as supported at 68 in a suitable chuck, for exampla'and a tool is shown at 69 for turning the periphery of the flange 65 down 'about the pole piece 6a as a center. VA lathe is contemplated for this purpose.

In Figure 9 is shown the step of turning the marginal edge of the pole piece Y1114, over Vat 66, I'hisl may bejdone by die elements or by center- 45' ing the pole piece 1a,l by means of the opening 24a and with a suitable tool 10 drawing'the margina' 'edge of the Vpole piece laterally to turn it over so that it will marginally Vreceive and ems brace the periphery ofy the ilange '65 of 4the case `50 56 upon assembly of the parts, thereby accurately Ydisposing the pole'piece'fa concentrically'with respect to the pole piecey1a. Itis to be under'- stood,` of course,'thatthe external diameterroi' 55 Y Lment 12, andV the internal 'diameter of the opening-1| being equal.

Y InFigure 5`the pole pieces 1 and l2' are shown sitioning means.. This is also true in Figure 9, but in Figure 3 the positioning means is shown as being formed before joining the p ole pieces 1 andrlZ. yThis may vary. p

I donotintendtobe limited to the precise de- 70 Atails shown or described.

Iclaimzf' Y In a loud speaker of the moving coil type, the combination of a diaphragm, an annular coilattached to saidV diaphragm, a casing part, an inner Y piece concentrically disposed independently of the attachment of said parts together. said positioning means comprising an annular ange on one part and the marginal edge of the other part being turned over laterally for telescopic en- 5 gagement with said flange.

PETER L. JENSEN. 

